Animals, for example mice, are used extensively in the examination of gene function, the development of drugs, and in other laboratory research applications. Often, the animals are constantly moving around, making it difficult to examine them for measurements of physiological parameters. However, mice are desirable mammalian models for examining locomotion kinematics, such as stride length, foot placement, and speed of ambulation.
A conventional method for measuring locomotion indices, such as stride, is by painting the feet of the mice and allowing the mice to walk on a clean, stationary, sheet of white paper. Analysis of the tracks created by the painted feet of the mice can be interpreted for derivation of the gait and stride indices. See for example, Gurny, M E et al., Science 264:1772-1775, 1994.
Another conventional method for measuring locomotion indices is described in Clarke and Still, Physiology and Behavior 66:723-729, 1999. The method involves gait analysis in a mouse using simultaneous video and reaction force analysis. An extension of a similar system described by Clarke for rats can be found in Physiological Behavior 58:415-419, 1995. The system for rats consisted of two cameras positioned below a U-shaped Plexiglas tunnel about 12 inches in length. One or two cameras positioned below the central part of the tunnel record under-views of the walking mouse. The images of the walking mouse are recorded on videotape. The videotape is then analyzed for locomotive indices. A minimum number of steps, about six, is needed for robust interpretation of the data. A longer tunnel would better provide the space required to obtain good data of the walking mouse. However, a longer tunnel would require additional cameras, movement of the camera approximately at the same speed as the walking mouse, or rotation of the cameras following an approaching mouse and a departing mouse. The last option results in some optical distortion as the viewing angle of the mouse changes, along with the distance to the mouse.